One of the proposed routes for mitigating the impact of greenhouse gases on the climate is to collect carbon dioxide (CO2), from the atmosphere or at source, and put it somewhere safe (usually underground). This is sometimes called CCS – carbon capture and storage (or sequestration), or CCUS – carbon capture, utilization and storage. It’s a controversial topic – many people would like simply to stop producing CO2, others that we should adapt to a new climate. It’s also a key component of the UK’s Net Zero target.

I’ll talk about the various facets of CC(U)S, including the quantities involved, where the CO2 might be put, with an emphasis on geological aspects, and what the downsides and hazards might be.